Abstract Arch
A dark area in the shape of a curving band. Generally there seems no good explanation for why such a shadow should occur.

Crosshatching
Two or more sets of parallel lines that intersect one another at an angle that are used to suggest grays.

Drop String
A row of dashes often, but not always, connected by a line. Another variation is to place the dashes so close together that they overlap.

Form Lines
Sets of lines, generally bowed, that provide a sense of volume to the art.

Picket Fence
Two rails roughly following the same path intersected by a number of pickets. A lot of variation can be found perhaps the most common is the replacement of one of the rails with either a drop string or a thicker spotting line.

Shingles
Straight parallel lines that are progressively shifted.

Shoulder Blot
Dark areas present in the shoulder regions.

Simple Hatching
One set of parallel lines used to suggest gray. Most do not make a distinction between simple and crosshatching as both are often present to suggest various shades of gray. I like to use this term because Kirby often uses simple hatching for large areas.